Supply air unit

ABSTRACT

A supply air unit including a supply air chamber, at least one mixing chamber nozzles or a nozzle gap through which a fresh airflow is conducted from the supply air chamber into the mixing chamber, a suction chamber into which a circulated airflow is sucked from an air-conditioned room space, and at least one outlet opening. At least one airflow controller through which an additional airflow is conducted from the supply air chamber into the suction chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Finnish patent application 20096195 filed 18 Nov. 2009.

TECHNICAL FIELD

The invention concerns a supply air unit.

BACKGROUND ART

Supply air units or air-conditioning beams usually comprise a supply air chamber, a mixing chamber and a heat exchanger. The flow of fresh air is brought from the supply air chamber into the mixing chamber, wherein the flow of fresh air is mixed with the circulated airflow, whereupon the combined airflow is conducted to the room space. The circulated airflow is conducted into the mixing chamber through a heat exchanger, in which the circulated airflow can be heated or cooled. Using the same supply air unit the room air can be cooled in the summer time and heated in the winter time. In the summer time, the circulated airflow of the room is cooled, and in the winter time it is heated in the supply air unit's heat exchanger. The flow of fresh air induces the circulated airflow to flow from the room through the heat exchanger into the mixing chamber.

The FI patent application 20060035 has presented a supply air unit and a method for controlling the airflow rate. The supply air unit comprises a supply air chamber, a heat exchanger, with which the circulated airflow conducted from the room space to be air-conditioned can be either cooled or heated, and a mixing chamber. A flow of fresh air is conducted from the supply air chamber through nozzles or a nozzle gap into the mixing chamber, in which the supply airflow induces the circulated airflow from the room to flow through the heat exchanger into the mixing chamber. In the mixing chamber, the flow of fresh air and the circulated airflow are combined, whereupon the combined airflow is conducted from the mixing chamber's outlet opening into the room space to be air-conditioned. The supply air unit also comprises an additional air opening, which is arranged on the flow path of the fresh airflow, separately from the nozzles or the nozzle gap, and a control device in connection with it for controlling the total rate of fresh airflow to be supplied from the supply air unit into the airconditioned room space. The additional air opening can be arranged in such a way that the fresh airflow will discharge from it either directly into the air-conditioned room space or into the mixing chamber.

The FI Patents 117682 B, 118236 B present supply air units comprising a supply air chamber, a heat exchanger, with which the circulated airflow conducted from the air-conditioned room space can be either cooled or heated, and a mixing chamber. The fresh airflow is conducted from the supply air chamber through nozzles or a nozzle gap into the mixing chamber, in which the supply airflow induces the circulated airflow from the room to flow through the heat exchanger into the mixing chamber. In the mixing chamber, the fresh airflow and the circulated airflow are combined, whereupon the combined airflow is conducted from the mixing chamber's outlet opening into the air-conditioned room space. These publications present various systems for controlling the induction ratio and for controlling either the rate of fresh airflow to be supplied into the mixing chamber or the rate of circulated airflow to be conducted from the air-conditioned room space into the mixing chamber.

The FI Patent 113798 B for its part presents a supply air unit, which comprises a supply air chamber and a mixing chamber. A fresh airflow is conducted from the supply air chamber through nozzles or a nozzle gap into the mixing chamber, in which the supply airflow induces the circulated airflow from the room to flow into the mixing chamber. In the mixing chamber, the fresh airflow and the circulated airflow are combined, whereupon the combined airflow is conducted from the mixing chamber's outlet opening into the air-conditioned room space. The publications present various systems for controlling the induction ratio and for controlling either the rate of fresh airflow to be supplied into the mixing chamber or the rate of circulated airflow to be conducted from the air-conditioned room space into the mixing chamber.

SUMMARY OF THE INVENTION

In the supply air unit according to the invention there is at least one airflow controller, through which an additional airflow is conducted from the supply air chamber into at least one suction chamber, from which the bypass flow of fresh air is guided into at least one mixing chamber.

The airflow controller is used to control the additional airflow into the suction chamber, whereby the rate of air to be supplied from the supply air unit into the air-conditioned room space can be controlled within definite limits without having to exchange the nozzles of the supply air unit. A certain minimum airflow rate must be conducted all the time through the nozzles, because this minimum rate is necessary in order to induce the circulated airflow and in this way to achieve a sufficient cooling and heating effect. Using the airflow controller it is possible to increase the supply air unit's total airflow rate 1-6 times compared with the minimum airflow rate.

When the additional airflow is conducted into the suction chamber, the rate of circulated airflow to be conducted from the air-conditioned room space into the suction chamber is reduced, but the airflow rate to be conducted from the suction chamber into the mixing chamber remains almost constant. Should the temperature of the additional airflow differ from the temperature of the circulated airflow of the air-conditioned room space, the additional airflow can be used for controlling the cooling or heating effect. On the other hand, the total fresh airflow rate to be supplied from the supply air unit into the air-conditioned room space (the fresh airflow supplied from the supply air unit's nozzles into the mixing chamber+the additional airflow supplied from the supply air chamber into the suction chamber and from this into the mixing chamber) can be increased or reduced without affecting the rate of combined airflow conducted from the mixing chamber into the room space and in this way the flow pattern. Besides, in this manner the additional airflow is distributed evenly through the suction chamber.

The solution according to the invention can very well be used, for example, in a situation where a constant pressure is maintained on the supply air side by using a constant pressure controller.

An advantageous embodiment of the invention in connection with the airflow controller uses an air-permeable fabric, through which the bypass flow of fresh air is conducted into the suction chamber. In this manner the airflow velocity is reduced to a considerably lower level than the velocity of the airflow discharging from the nozzles. The lower velocity of the airflow for its part results in a lower noise level. Due to the lower velocity of the airflow, a higher pressure may be used in the supply air chamber. Owing to the low flow velocity of the additional air, the supply air unit's air distribution characteristics are determined based on the nozzle airflow and a possible induction controller located in the outlet opening of the mixing chamber.

In another advantageous embodiment of the invention, the supply air unit also comprises at least one heat exchanger. In such a solution the additional air to be supplied through the suction chamber and the heat exchanger into the mixing chamber can be after-heated or after-cooled in the heat exchanger. This may be required, for example, in a situation where the supply air unit is located in a negotiation room, where a large supply airflow may cause over- or under-cooling of the negotiation premises. By after-heating or after-cooling the additional airflow conducted through the suction chamber and the heat exchanger into the mixing chamber a suitable temperature can be controlled for the airflow combined in the mixing chamber.

In the following, the invention will be described by referring to some advantageous embodiments of the invention shown in the figures of the appended drawings, but there is no intention to restrict the invention to these alone.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical cross-sectional view of a supply air unit, in which the invention can be applied.

FIG. 2 is a vertical cross-sectional view of another supply air unit, in which the invention can be applied.

FIG. 3 is an axonometric view of an elongated supply air unit, in which the invention can be applied.

FIG. 4 is an axonometric view of another round supply air unit, in which the invention can be applied.

FIG. 5 is a vertical cross-sectional view of a third supply air unit, in which the invention can be applied.

FIG. 6 is a vertical cross-sectional view of a fourth supply air unit, in which the invention can be applied.

FIG. 7 shows an airflow controller solution according to the invention.

FIG. 8 shows another airflow controller solution according to the invention.

FIG. 9 shows a third airflow controller solution according to the invention.

FIG. 10 shows a fourth airflow controller solution according to the invention.

DESCRIPTION OF ADVANTAGEOUS EMBODIMENTS

FIG. 1 is a vertical cross-sectional view of a supply air unit, in which the invention can be applied.

The supply air unit 100 comprises a supply air chamber 10, which comprises a horizontal roof panel 11, below it and located at a distance from it a parallel ceiling panel 12, a first vertical outer side wall 13 a, a second vertical outer side wall 13 b, a first vertical inner side wall 14 a and a second vertical inner side wall 14 b. The top edge of the first vertical outer side wall 13 a joins the left side edge of the roof panel 11, and the top edge of the second vertical outer side wall 13 b joins the right side edge of the roof panel 11. The top edge of the first vertical inner side wall 14 a joins the left side edge of the ceiling panel 12, and the top edge of the second vertical inner side wall 14 b joins the right side edge of ceiling panel 12. The bottom edge of the first vertical outer side wall 13 a is joined to the bottom edge of the first vertical inner side wall 14 a by a first connecting wall 15 a, and the bottom edge of the second vertical outer side wall 13 b is joined to the bottom edge of the second vertical inner side wall 14 b by a second connecting wall 15 b. The supply air chamber 10 is thus formed by two separate lower chambers 10 b 1, 10 b 2, which are in connection with each other by way of one one-piece upper chamber 10 a.

The fresh airflow L1 is brought into supply air chamber 10 through a horizontal X-X fitting 16 connected to the first vertical outer side wall 13 a of supply air chamber 10. The connection 16 for supply air may be located in the roof panel 11, and not in the supply air chamber's 10 outer side wall 13 a.

The supply air unit 100 also comprises two vertical heat exchangers 30 a, 30 b, which are located at a distance from each other and have a rectangular cross-sectional shape and which at their top end are supported against the supply air chamber's 10 ceiling wall 12. A suction chamber 40 with a rectangular cross-sectional shape is formed in the space between the heat exchangers 30 a, 30 b. The lower part of suction chamber 40 contains a bottom plate 50, which is supported against the bottom end of the heat exchangers 30 a, 30 b. The middle part 52 of bottom plate 50 has openings, through which the circulated airflow L2 can be conducted from the air-conditioned room space into the suction chamber 40. A first mixing chamber 20 a with a rectangular cross-sectional shape is formed in the space between the first heat exchanger 30 a and the supply air chamber's 10 first vertical inner side wall 14 a. A second mixing chamber 20 b with a rectangular cross-sectional shape is formed in the space between the second heat exchanger 30 b and the supply air chamber's 10 second vertical inner side wall 14 b. In the ceiling of the first mixing chamber 20 a, that is, in the ceiling panel 11 of supply air chamber 10, there is a first nozzle row 60 a, through which the fresh airflow L1 is conducted from supply air chamber 10 into the first mixing chamber 20 a. In the ceiling of the second mixing chamber 20 b, that is, in the ceiling panel 11 of supply air chamber 10, there is a second nozzle row 60 b, through which the fresh airflow L1 is conducted from supply air chamber 10 into the second mixing chamber 20 a.

In the lower part of the first mixing chamber 20 a a first outlet opening 25 a is formed, which is limited by the first connecting wall 15 a and by the bottom plate's 50 left side edge 51 a. In the lower part of the second mixing chamber 20 b a second outlet opening 25 b is formed, which is limited by the second connecting wall 15 b and by the bottom plate's 50 right side edge 51 b. Both outlet openings 25 a, 25 b are shaped in such a way that the airflow is guided from mixing chamber 20 a, 20 b in the air-conditioned room space to the side, essentially in the direction of the room's ceiling surface.

In the suction chamber's 40 ceiling, that is, in supply air chamber's 10 ceiling panel 11, the supply air unit 100 also comprises at least one airflow controller 70, through which an additional airflow L3 can be conducted from supply air chamber 10 into suction chamber 40.

In each mixing chamber 20 a, 20 b the fresh airflow L1 builds up a vacuum, which will suck or induce the circulated airflow L2 from the air-conditioned room space into suction chamber 40 and from this further through heat exchangers 30 a, 30 b into mixing chambers 20 a, 20 b. The additional airflow L3 is also sucked from suction chamber 40 through heat exchangers 30 a, 30 b into mixing chambers 20 a, 20 b. In mixing chambers 20 a, 20 b, the fresh airflow L1, the additional airflow L3 and the circulated airflow L2 form a combined airflow LA. The circulated airflow L2 and the additional airflow L3 can be cooled or heated in heat exchangers 30 a, 30 b. The combined airflow LA discharges from the outlet opening 25 a, 25 b located in the lower part of each mixing chamber 20 a, 20 b into the air-conditioned room space to the side, essentially in the direction of the room's ceiling surface.

The supply air unit 100 is symmetrical in relation to the vertical central axis Y-Y.

The supply air unit shown in FIG. 1 may be formed by an elongated body having an essentially rectangular cross-sectional shape or by a round body. When the supply air unit is round, the heat exchangers 30 a, 30 b are formed by one ring-shaped heat exchanger, which is surrounded by a ring-shaped mixing chamber 20 a, 20 b, in whose lower part there is a ring-shaped outlet opening 25 a, 25 b. Hereby, the supply air chamber's 10 lower part 10 b 1, 10 b 2 is also a ring-shaped chamber, and the upper part 10 a is a cylindrical chamber. The outer side wall 13 a, 13 b of the supply air chamber 10 in a round supply air unit can have a cylindrical or, for example, a rectangular or polygonal shape, whereby the roof panel 11 is also adapted to the shape of the outer side wall 13 a, 13 b.

FIG. 2 is a vertical cross-sectional view of another supply air unit, in which the invention can be applied. This embodiment corresponds to the left side of the embodiment shown in FIG. 1, that is, to the part located on the left side of the vertical central axis Y-Y. Thus, in this embodiment there is only one mixing chamber 20 and only one heat exchanger 30. The suction chamber 40 is limited to the space in between heat exchanger 30 and the right-hand outer side wall 13 c. In this embodiment, the cross-sectional shape of mixing chamber 20, heat exchanger 30 and suction chamber 40 is essentially rectangular.

FIG. 3 is an axonometric view of an elongated supply air unit, in which the invention can be applied. Thus, the supply air unit 100 is here formed by an elongated body having an essentially rectangular cross-section. In the supply air chamber's ceiling panel 12 there are three airflow controllers 70 a, 70 b, 70 c, through which an additional airflow can be conducted from the supply air chamber into the suction chamber 40 located between the heat exchangers 30 a, 30 b. The supply air unit can, of course, also have a square shape.

FIG. 4 is an axonometric view of a round supply air unit, in which the invention can be applied. Thus, the supply air unit 100 is here formed by a body having a round shape. In the supply air chamber's ceiling panel 12 there is one airflow controller 70, through which a fresh airflow can be conducted from the supply air chamber into the inner cylindrical suction chamber of the ring-shaped heat exchanger.

FIG. 5 is a vertical cross-sectional view of a third supply air unit, in which the invention can be applied. The supply air chamber's 10 cross-section is formed by an upper rectangular section and by a lower triangular section. Under the supply air chamber 10 there is a horizontal bottom plate 50, which has edge parts 51 a, 51 b folded obliquely upwards. The supply air unit also comprises side walls 14 a, 14 b, whose top edges join the bottom corners of the supply air chamber's 10 rectangular upper part and which are directed obliquely downwards. The first side wall 14 a and the bottom plate's first edge part 51 a form in between them a first mixing chamber 20 a. The second side wall 14 b and the bottom plate's second edge part 51 b form in between them a second mixing chamber 20 b. In the supply air chamber's 10 triangular lower part there is on each edge an airflow controller 70 a, 70 b, through which an additional airflow L3 is conducted from supply air chamber 10 into suction chamber 40, from which the additional airflow L3 is sucked along with the circulated airflow L2 into mixing chamber 20 a, 20 b.

In connection with the bottom plate's 51 first edge part 51 a a first damper 200 a is mounted, with which the induction ratio of the first mixing chamber 20 a can be controlled. In connection with the bottom plate's 51 second edge part 51 b a second damper 200 b is mounted for controlling the induction ratio of the second mixing chamber 20 b. The fresh airflows L1 discharging from nozzles 60 a, 60 b are directed into mixing chambers 20 a, 20 b and they induce the circulated airflow L2 to flow through the openings in the bottom plate's 50 middle part 52 into suction chamber 40 and from this further into mixing chambers 20 a, 20 b. By raising and lowering the dampers 200 a, 200 b the rate of circulated airflow L2 conducted from suction chamber 40 into mixing chambers 20 a, 20 b can be controlled, whereby the induction ratio will change.

FIG. 6 is a vertical cross-sectional view of a fourth supply air unit, in which the invention can be applied. The supply air chamber's 10 cross-section is formed by an upper triangular section and by a lower triangular section. Inner side walls 51 a, 51 b, which are directed obliquely downwards, are attached to the side walls of the supply air chamber's 10 lower triangular section. The supply air unit also comprises outer side walls 14 a, 14 b, which are formed by upper vertical sections 14 a 1, 14 b 1 and by sections 14 a 2, 14 b 2 directed obliquely downwards. A first suction chamber 40 a is formed in between the vertical section 14 a 1 of the first outer side wall 14 a and the first side wall of the supply air chamber's 10 rectangular upper section. A second suction chamber 40 b is formed in between the vertical section 14 b 1 of the second outer side wall 14 b and the second side wall of the supply air chamber's 10 rectangular upper section. The oblique section 14 a 2 of the first outer side wall 14 a and the first inner side wall 51 a form in between them a first mixing chamber 20 a. The oblique section 14 b 2 of the second outer side wall 14 b and the second inner side wall 51 b form in between them a second mixing chamber 20 b. In the side walls of the supply air chamber's 10 rectangular upper section there is an airflow controller 70 a, 70 b, through which an additional airflow L3 is conducted from supply air chamber 10 into suction chambers 40 a, 40 b, from which the additional airflow L3 is sucked along with the circulated airflow L2 into mixing chambers 20 a, 20 b.

In connection with the vertical section 14 a 1 of the first outer side wall 14 a a first damper 200 a is mounted for controlling the induction ratio of the first mixing chamber 20 a. In connection with the vertical section 14 b 1 of the second outer side wall 14 b a second damper 200 b is mounted for controlling the induction ratio of the second mixing chamber 20 b. The fresh airflows L1 discharging from nozzles 60 a, 60 b are directed into mixing chambers 20 a, 20 b and they induce the circulated airflow L2 to flow into suction chambers 40 a, 40 b and from these further into mixing chambers 20 a, 20 b. By turning the dampers 200 a, 200 b it is possible to control the rate of circulated airflow L2 conducted from suction chambers 40 a, 40 b into mixing chambers 20 a, 20 b, whereby the induction ratio is changed.

FIG. 7 shows an airflow controller solution according to the invention. The top margin of the side shows a cross-section of the airflow controller and the bottom margin of the side shows a view of the airflow controller seen from below. The airflow controller is here based on a disc valve comprising a bottom part 71, which is supported against the edges of an opening 12 a located in a ceiling panel 12. The bottom part 71 may be formed, for example, by a collar, which fits on the edges of the opening 12 a in ceiling panel 12, and by a transverse part, in the middle of which there is a threaded hole 72. Inside the collar there is thus formed an opening, which opens into the opening 12 a in the ceiling panel 12 and which is limited by the transverse part only. The disc valve also comprises a control disc 73, which through a threaded pin 74 is supported in the threaded hole 72 located in the middle of bottom part 71. The rate of air discharging from the airflow controller can be controlled by controlling the distance of control disc 73 from bottom part 71 by turning the control disc 73 in the way indicated by arrow S1. To the outer periphery of control disc 73 an air-permeable fabric 75 is also mounted, which extends to the stretch between disc 73 and ceiling panel 12. The air-permeable fabric 75 may consist, for example, of gauze. The top end of the air-permeable fabric 75 must be supported against the ceiling panel 12 or the bottom part 71 in such a way that the air-permeable fabric 75 can rotate along with the control disc 73 when the disc valve is opened or closed by turning the control disc 73. An additional airflow L3 is conducted from supply air chamber 10 through the opening 12 a of the supply air chamber's 10 ceiling panel 12 and through the opening in the disc valve's bottom part 71 and then further through the air-permeable fabric 75 into the lower suction chamber 40 of airflow controller 70.

FIG. 8 shows another airflow controller solution according to the invention. The top margin of the side shows a cross-section of the airflow controller, and the bottom margin of the side is a view of the airflow controller seen from below. The airflow controller 80 comprises a bottom part 81, which is supported against the edges of an opening 12 a in a ceiling panel 12 and which has a section comprising sector-like openings. The bottom part 81 may be formed, for example, by a collar, which fits against the opening 12 a in ceiling panel 12 and by a central section, which comprises sector-like openings and in the middle of which there is a threaded hole 82. Sector-like openings are thus formed inside the collar in its central section and they open into the opening 12 a in ceiling panel 12. The airflow controller 80 also comprises a damper 83, which has sector-like openings 83 a. The damper 83 is supported through a threaded bolt 84 in a threaded hole 82 located in the middle of bottom part 81. The rate of air discharging from the airflow controller 80 can be controlled by turning damper 83 in the way indicated by arrow S1, whereby the extent of overlapping is controlled between the bottom part's 81 sector-like openings 81 a and the damper's 83 sector-like openings 83 a. Between the bottom plate 81 and the bottom surface of ceiling panel 12 an air-permeable fabric 85 can also be mounted, which preferably is gauze. An additional airflow L3 is conducted from supply air chamber 10 through the opening 12 a in the supply air chamber's 10 ceiling panel 12 and through the air-permeable fabric 85 into airflow controller 80, from whose openings 81 a, 83 a the fresh airflow L1 discharges into the airflow controller's 80 lower suction chamber 40.

FIG. 9 shows a third airflow controller solution according to the invention. The top margin of the side shows a cross-section of the airflow controller and the bottom margin of the side is a view of the airflow controller seen from below. The airflow controller 90 comprises a bottom part 91, which is supported against the edges of an opening 12 a in ceiling panel 12. The bottom part 91 may be formed, for example, by a collar, which fits against the edges of openings 12 a in ceiling panel 12. Inside the collar an opening is thus formed, which opens into the opening 12 a in ceiling panel 12. The airflow controller 90 also comprises a bottom cylinder 91 b, whose inner end is supported against the bottom part 91 and whose outer end is closed by a first cover plate 91 c. The airflow controller 90 also comprises a control cylinder 93, which is located on the outer surface of the bottom cylinder's 91 b casing and whose outer end is closed by a second cover plate 93 c. The casing of bottom cylinder 91 b has first openings 91 a and the casing of the outer control cylinder 93 has second openings 93 a The control cylinder 93 rotates on the outer surface of the bottom cylinder's 91 b casing in the manner indicated by arrow S1, whereby it is possible to control the overlapping between the control cylinder's 93 openings 93 a and the bottom cylinder's 91 b openings 91 a, that is, how much airflow there will be through the airflow controller 90. Through the control cylinder's 93 bottom plate 93 a a threaded bolt 94 extends, which fits into a threaded hole 92 in the bottom cylinder's 91 b cover plate 91 c, 92. The threaded bolt 94 can be used to lock the control cylinder 93 to the bottom cylinder 91 b in a desired position. To the inner surface of the bottom cylinder's 91 b casing an air-permeable fabric 95 can also be mounted, which preferably is gauze. An additional airflow L3 is conducted from supply air chamber 10 through the opening 120 a in the supply air chamber's 10 ceiling panel 12 into the inner bottom cylinder 91 b and then further through the air-permeable fabric 95, the bottom cylinder's 91 b openings 91 a and the control cylinder's 93 openings 93 a into suction chamber 40.

FIG. 10 shows a fourth airflow controller solution according to the invention. In this embodiment, the airflow controller 100 comprises an actuator 110, which controls a closing device 115, which preferably is a valve disc. Actuator 110 is fastened by a fastening band 105 to the supply air unit's ceiling panel 12, that is, to the suction chamber's 40 roof panel. The closing device 105 closes and opens an opening 12 a in ceiling panel 12. The actuator 110 may be, for example, a step motor, which is controlled by a control unit 120 located in the air-conditioned room space. From the control unit 120 located in the air-conditioned room space it is possible to carry on a step-less control of the supply air unit's additional airflow L3. FIG. 10 does not show any fabric in connection with the airflow controller 100, but it is of course possible to add to the airflow controller 100, for example, the fabric solution 75 presented in the embodiment shown in FIG. 7.

In the embodiment shown in FIG. 1, the suction chamber 10 has a one-piece top section 10 a and an outer section 10 b 1, 10 b 2 outside the mixing chambers 20 a, 20 b. Both in connection with a square and a round supply air unit the supply air chamber 10 may also be formed by a one-piece top section 10 a only. The supply air chamber's 10 inner side walls 14 a, 14 b hereby extend to the roof panel 11 and form the supply air unit's outer side walls. The supply air connection 16 may be located in the supply air chamber's 10 outer side wall 14 a, 14 b or in the roof panel 11.

In the embodiment shown in FIG. 2, the suction chamber 10 has a one-piece top section 10 a and an outer section 10 b outside the mixing chamber 20. The supply air chamber 10 may also be formed by a one-piece top section 10 a only. The supply air chamber's 10 inner side wall 14 a hereby extends to the roof panel 11 and forms the supply air unit's outer side wall. The supply air connection 16 may be located in the supply air chamber's 10 outer side wall 14 a or in the roof panel 11.

In the embodiment shown in FIG. 3 there are three airflow controllers 70 a, 70 b, 70 c and in FIG. 4 there is one airflow controller 70. The number of airflow controllers is determined by the rate of fresh air required. In the supply air unit according to the invention there is at least one airflow controller.

In the embodiments shown in the figures, the fresh airflow L1 is supplied from the supply air chamber 10 through nozzles 60, 60 a, 60 b into mixing chambers 20, 20 a, 20 b. The nozzles 60, 60 a, 60 b can be replaced by a nozzle gap, through which the fresh airflow L1 is conducted from supply air chamber 10 into the mixing chambers 20, 20 a, 20 b.

The above presentation presented only a few advantageous embodiments of the invention, and it is obvious to a person skilled in the art that numerous modifications can be made to them within the scope defined in the appended claims. 

1. A supply air unit, comprising: a supply air chamber, at least one mixing chamber, nozzles or a nozzle gap, through which a fresh airflow is conducted from the supply air chamber to said at least one mixing chamber, at least one suction chamber into which a circulated airflow is conducted from an air-conditioned room space, at least one outlet opening through which a combined airflow located in said at least one mixing chamber from the fresh airflow and the circulated airflow is conducted into the air-conditioned room space, and at least one airflow controller through which is conducted an additional airflow from the supply air chamber to said at least one suction chamber, from which the additional airflow is sucked along with the circulated airflow into said at least one mixing chamber.
 2. The supply air unit according to claim 1, further comprising: at least one heat exchanger comprising a supply side and an opposite outlet side, whereby said at least one mixing chamber is located in connection with the outlet side of said at least one heat exchanger, and said at least one suction chamber is located in connection with the supply side of said at least one heat exchanger, whereby the circulated airflow and the additional airflow travel from said at least one suction chamber through said at least one heat exchanger from the supply side into said at least one mixing chamber located at the outlet side.
 3. The supply air unit according to claim 1, further comprising: a horizontal ceiling panel, two elongated parallel heat exchangers located at a distance from each other, the two elongated parallel heat exchangers comprising top ends supported against a lower surface of the ceiling panel, an elongated suction chamber, which is located in a space between the heat exchangers, at a supply side of the heat exchangers, an elongated mixing chamber located outside each heat exchanger at an outlet side of the heat exchangers, a supply air chamber comprising elongated lower sections located outside the mixing chambers and a one-piece top section, which connects the lower sections and which is located in the space between the horizontal ceiling panel and the parallel roof panel located at a distance from the one-piece top section, nozzles which are located in the ceiling of the mixing chambers in the ceiling panel, and through which a fresh airflow is conducted from the supply air chamber into the mixing chambers, a bottom plate which is supported against a lower end of the heat exchangers and which in its middle part comprises openings, through which the circulated airflow is conducted from the air-conditioned room space into the suction chamber, an outlet opening which is located in the lower part of each mixing chamber and which is limited by the bottom surfaces of the lower sections of the supply air chamber and by the outer edges of the bottom plate, and at least one airflow controller which is located in the ceiling of the suction chamber in the ceiling panel, and through which an additional airflow is conducted from the supply air chamber into the suction chamber, from which the additional airflow is sucked through the heat exchangers into the mixing chambers.
 4. The supply air unit according to claim 1, further comprising: a horizontal ceiling panel, an elongated heat exchanger having a top end supported against the lower surface of the ceiling panel, an elongated suction chamber located in a space between the heat exchanger and the vertical outer side wall at the supply side of the heat exchanger, an elongated mixing chamber which is located at the outlet side of the heat exchanger, a supply air chamber comprising an elongated lower section located outside the mixing chamber and an upper section, which is located in a space between the horizontal ceiling panel and the horizontal roof panel, nozzles which are located in the ceiling of the mixing chamber in the ceiling panel, and through which a fresh airflow is conducted from the supply air chamber into the mixing chamber, a bottom plate which is supported against the lower end of the heat exchanger, and the lower edge of the vertical outer side wall, and wherein a middle part of the bottom plate comprises openings, through which a circulated airflow is conducted from the air-conditioned room space into the suction chamber, an outlet opening which is located in the lower part of the mixing chamber and which is limited by the bottom surface of the lower section of the supply air chamber and by the outer edge of the bottom plate, at least one airflow controller which is located in the ceiling of the suction chamber in the ceiling panel, and through which an additional airflow is conducted from the supply air chamber into the suction chamber, from which the additional airflow is sucked through the heat exchanger into the mixing chamber.
 5. The supply air unit according to claim 1, further comprising: a horizontal round ceiling panel, a ring-shaped heat exchanger having a top end supported against a lower surface of the ceiling panel, a ring-shaped suction chamber located inside the ring-shaped heat exchanger at a supply side of the ring-shaped heat exchanger, a ring-shaped mixing chamber located outside the ring-shaped heat exchanger at outlet side of the ring-shaped heat exchanger, a supply air chamber comprising a lower section located outside the ring-shaped mixing chamber, and a one-piece upper section to which the lower ring-shaped section is joined and which is located in a space between the horizontal ceiling panel and the horizontal roof panel, nozzles which are located in a ceiling of the ring-shaped mixing chamber in the ceiling panel, and through which a fresh airflow is conducted from the supply air chamber into the mixing chamber, a bottom plate which is supported against the lower end of the ring-shaped heat exchanger, wherein a middle part of the bottom plate comprises openings, through which a circulated airflow is conducted from the air-conditioned room space into the suction chamber, a ring-shaped outlet opening which is located in the lower part of the ring-shaped mixing chamber and which is limited by the bottom surface of the lower ring-shaped section of the supply air chamber and by an outer edge of the bottom plate, and at least one airflow controller which is located in the ceiling of the suction chamber in the ceiling panel, and through which an additional airflow is conducted from the supply air chamber into the suction chamber, from which the additional airflow is sucked through the heat exchanger into the mixing chamber.
 6. The supply air unit according to claim 1, wherein said at least one airflow controller comprises a disc valve comprising: a bottom part which is supported against edges of a hole in the ceiling of the suction chamber, a control disc, and a threaded pin through which the control disc is supported to rotate in a threaded hole located in the middle of the bottom part, whereby the rate of air discharging from the airflow controller can be controlled by controlling a distance of the control disc from the bottom part by turning the control disc.
 7. The supply air unit according to claim 1, said at least one airflow controller comprises a sector slot air valve, comprising: a bottom part which is supported against the edges of an opening in the ceiling of the suction chamber and which has a section comprising sector-like openings, a damper which has sector-like openings, and a threaded bolt which extends through a hole in the damper and fits into a threaded hole in the middle of the bottom plate, whereby the rate of air discharging from the airflow controller can be controlled by controlling the extent of overlapping between the sector-like openings of the bottom part and the sector-like openings of the damper by turning the damper.
 8. The supply air unit according to claim 1, wherein said at least one airflow controller comprises a cylinder, which opens up sector-by-sector and which comprises: a bottom part which is supported against the edges of an opening in the ceiling of the suction chamber, a bottom cylinder having an inner end supported against a bottom plate having an outer end closed by a first cover plate, wherein a casing of the bottom cylinder comprises first openings, a control cylinder which is located on the outer surface of the casing of the bottom cylinder, the control cylinder comprising an outer end is closed by a second cover plate, the control cylinder further comprising a casing comprising second openings, and a threaded bolt which extends through a hole in the cover plate of the control cylinder and fits into a threaded hole in the cover plate of the bottom cylinder, whereby the rate of air discharging from the airflow controller can be controlled by controlling the extent of overlapping between the openings of the control cylinder and the openings of the bottom cylinder by turning the control cylinder.
 9. The supply air unit according to claim 6, wherein the airflow controller further comprises an air-permeable fabric through which the bypass flow of fresh air is conducted. 